RAT!!!

We seem to have a RAT in the house altough we have actually not seen it, but I can hear something running around in the cavitiy at night and three times over the last few days, when I came into the kitchen in the morning, the bit of the bin liner that overhangs the lid has been ripped and bits of it led to a cupboard that has a gap underneath. We took the board under the cupboard out and found these pieces of binliner plus some green, woolly stuff that is apparently insulation material that must be stuck to our "visitor". There must be a hole in the wall or by a pipe somewhere, but we cannot see it without taking all the kitchen furniture in that corner out, sink, dishwasher etc. The council man seems to think it could be a squirrel, since we have lots of them in the garden and told me to get a life trap (illegal to poison squirrels, apparently) which I have now put near the place where it seems to come out. No luck, although baited with peanut butter and Cadbury's Fruit and Nut. We don't keep food out and keep all kitchen and utility doors closed to the rest of the house. If there is no other food, why does it not go into the trap? It is obviously attracted to the bin because it still smells of waste, even though I take the trash out every night. If I move the bin out of the utility room and take it out of the house, will the rat try to find food elsewhere in the house? Can they squeeze through closed doors?Needless to say, I am completely worn out due to no sleep (listening to that scratching noise in the wall all night) and disinfecting everything all day long.I saw on another, older threat that someone has caught a rat with a cage trap, any tips would be extremely welcome! DD now refuses to be on her own at any time in the house and won't go to bed etc. and DS starts to panic as well. DP, of course, leaves it all to me - as though I was some type of expert on these things. I thought my role was to stand on a chair and scream and his role was to rescue me from the beast! During the day, btw, I don't hear it at all.